Pose measurement in a positioning apparatus

Abstract

A positioning apparatus with a pose measurement function includes a first and second kinematic links, a first measuring link attached to the second kinematic link, a joint connecting the first and second kinematic links, and a sensor capturing a measurement device. Either the measurement device or the sensor is arranged at the first measuring link and is movable jointly with the second kinematic link. The other one is arranged at the first kinematic link and is movable jointly with the first kinematic link. An attachment location of the first measuring link lies closer to an end of the second kinematic link that is remote from the joint than to the joint. The positioning apparatus is configured to ascertain, based on data captured by the sensor, a first relative pose value corresponding to the degree of freedom of the joint and a further relative pose value for another degree of freedom.

The invention claimed is: 
     
       1. A positioning apparatus with a pose measurement function, the positioning apparatus comprising:
 a first kinematic link; 
 a second kinematic link; 
 a first measuring link attached to the second kinematic link; 
 a joint that connects the first and second kinematic links; 
 a measurement device; and 
 a sensor configured to capture data indicative of pose of the measurement device relative to the sensor, 
 wherein: 
 a first one of the measurement device and the sensor is arranged at the first measuring link and is movable jointly with the second kinematic link relative to the first kinematic link, 
 an other one of the measurement device and the sensor is arranged at least indirectly at the first kinematic link and is movable jointly with the first kinematic link relative to the second kinematic link, 
 the second kinematic link includes a first end opposite a second end, 
 the joint is proximate the first end, 
 an attachment location of the first measuring link at the second kinematic link lies closer to the second end than to the first end, and 
 the positioning apparatus is configured to ascertain, based on data captured by the sensor, a first relative pose value corresponding to a degree of freedom of the joint and a further relative pose value for another degree of freedom. 
 
     
     
       2. A coordinate measuring machine comprising the positioning apparatus of  claim 1 . 
     
     
       3. The positioning apparatus of  claim 1 , wherein the sensor is configured to optically capture the data indicative of the pose of the measurement device by at least one of (i) optically imaging the measurement device and (ii) capturing optical signals transmitted by the measurement device. 
     
     
       4. The positioning apparatus of  claim 1 , further comprising:
 a second measuring link attached to the first kinematic link, 
 wherein the other one of the measurement device and the sensor is attached to the second measuring link. 
 
     
     
       5. The positioning apparatus of  claim 1 , wherein the first measuring link and the first kinematic link are not in contact with one another. 
     
     
       6. The positioning apparatus of  claim 1 , wherein the first measuring link is not directly connected to the joint. 
     
     
       7. The positioning apparatus of  claim 1  wherein the first measuring link is received at least partially in a hollow body section of the second kinematic link. 
     
     
       8. The positioning apparatus of  claim 1  wherein the sensor and the measurement device are arranged opposite one another in a region of the joint. 
     
     
       9. The positioning apparatus of  claim 1  wherein an absolute pose value of at least one reference location of the positioning apparatus is determined based on at least one of the relative pose values. 
     
     
       10. The positioning apparatus of  claim 9 , further comprising:
 a third kinematic link; 
 a second measuring link; and 
 a second joint that connects the third kinematic link to the second kinematic link, wherein: 
 the positioning apparatus is configured to ascertain a relative pose value between the first and second measuring links, and 
 the absolute pose value of the reference location is determined based on the relative pose value. 
 
     
     
       11. The positioning apparatus of  claim 1  wherein:
 the joint comprises a pose sensor, and 
 a final pose value is ascertainable based both on measurement values from the pose sensor and on the first and further relative pose values captured by the sensor. 
 
     
     
       12. The positioning apparatus of  claim 1  further comprising:
 a radiation source configured to generate electromagnetic radiation as a signal of the measurement device, 
 wherein the sensor is configured to capture the radiation. 
 
     
     
       13. The positioning apparatus of  claim 1  wherein the sensor is spatially resolving. 
     
     
       14. The positioning apparatus of  claim 1  wherein a relative arrangement of the sensor and the measurement device is ascertainable based on the data captured by the sensor. 
     
     
       15. The positioning apparatus of  claim 1 , wherein:
 the first relative pose value relates to a bending degree of freedom, and 
 the sensor is arranged closer to the attachment location than to the joint. 
 
     
     
       16. The positioning apparatus of  claim 15 , further comprising:
 a second sensor, 
 wherein the relative pose value is ascertained based on a difference of respective capturing results of the sensor and the second sensor. 
 
     
     
       17. The positioning apparatus of  claim 1 , further comprising:
 a plurality of sensors including the sensor, 
 wherein relative pose values with respect to six spatial degrees of freedom are ascertainable based on the plurality of sensors. 
 
     
     
       18. The positioning apparatus of  claim 1 , wherein the positioning apparatus is a robot configured to measure objects. 
     
     
       19. A method for operating a positioning apparatus having a first kinematic link, a second kinematic link, a first measuring link attached to the second kinematic link, a joint connecting the first and second kinematic links, a measurement device, and a sensor, wherein a first one of the measurement device and the sensor is arranged at the first measuring link and is movable jointly with the second kinematic link relative to the first kinematic link, wherein an other one of the measurement device and the sensor is arranged at least indirectly at the first kinematic link and is movable jointly with the first kinematic link relative to the second kinematic link, wherein the second kinematic link has a first end opposite a second end, wherein the joint is proximate the first end, and wherein an attachment location of the first measuring link at the second kinematic link lies closer to the second end than to the first end, the method comprising:
 sensing, using the sensor, data indicative of pose of the measurement device relative to the sensor; and 
 ascertaining at least one relative pose value based on the sensing. 
 
     
     
       20. The method of  claim 19 , further comprising:
 fixing, using the positioning apparatus, a relative arrangement, with respect to an object to be measured, of at least one of the positioning apparatus, a tool attached to the positioning apparatus, and a measuring sensor attached to the positioning apparatus; and 
 ascertaining a measurement value relating to the object, taking into account the relative pose value, 
 wherein the measurement value includes an object coordinate value. 
 
     
     
       21. The positioning apparatus of  claim 3 , wherein:
 the measurement device includes an optically capturable mark; and 
 the sensor is configured to optically capture the data indicative of the pose of the measurement device by optically imaging the optically capturable mark.